Inertial Modes in the Earth'S Fluid Outer Core

  1. D. E. Smylie and
  2. Raymond Hide
  1. Keith D. Aldridge,
  2. L. Ian Lumb and
  3. Gary A. Henderson

Published Online: 29 MAR 2013

DOI: 10.1029/GM046p0013

Structure and Dynamics of Earth's Deep Interior

Structure and Dynamics of Earth's Deep Interior

How to Cite

Aldridge, K. D., Lumb, L. I. and Henderson, G. A. (1988) Inertial Modes in the Earth'S Fluid Outer Core, in Structure and Dynamics of Earth's Deep Interior (eds D. E. Smylie and R. Hide), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM046p0013

Author Information

  1. Department of Earth and Atmospheric Science, York University, North York, Ontario, M3j 1P3, Canada

Publication History

  1. Published Online: 29 MAR 2013
  2. Published Print: 1 JAN 1988

ISBN Information

Print ISBN: 9780875904504

Online ISBN: 9781118666562



  • Earth—Core—Congresses;
  • Geodynamics—Congresses


Several inertial waves previously identified by Aldridge and Lumb [1987] in the long period gravimetric data of Melchior and Ducarme [1986], have been observed in a record from the same laboratory over 1440 days during the period 1982 to 1986. In the original data, collected following the Mindanao (20 November 1984) and Hindu Kush (30 December 1983) earthquakes, 8 inertial waves were tentatively identified by close proximity of their frequencies to those of a Poincaré Earth model for the fluid outer core. All of the waves identified in the earlier record persist in the longer record, thus verifying the significance of the earlier identification. All the waves decay more rapidly than would be expected from Ekman dissipation which suggests other mechanisms, possibly of hydromagnetic origin, for the damping of these waves. Alternatively the waves may be critically damped due to irregularity in the core-mantle boundary (CMB). Both of these models and others for the decay of the observed waves can be directly evaluated using the high-quality gravimetric data which is now available. The inertial waves identified here will serve as a precise tool for subsequent evaluation of models for core dynamics and the geodynamo.